This invention relates to a positioning device which permits accurate high speed positioning of parts, probes, machine tools and the like and more specifically to a lead screw and follower drive arrangement which has reduced inertial load and component friction as well as increased component stiffness.
In positioning devices of the screw and follower drive type, it is necessary for accurate high speed positioning that the inertial load and component friction are minimum while the component stiffness is maximum. Many prior art lead screw and nut device utilize circulating ball bearings between the nut and screw which reduce component friction to a minimum. However, such arrangements are notoriously expensive and still suffer from the backlash problem.
Other prior art lead screw and nut devices have utilized a pair of axially spaced apart nut followers which may be rotatively adjusted relative to each other and the lead screw to eliminate backlash. However, such mechanisms have extremely high component friction and to utilize circulating ball bearings in each nut should be prohibitively expensive.